Bugs: Nature is zoo's pest control | VIDEO

MOLLY BARTELS / Courier &amp; Press
Mesker Park Zoo &amp; Botanic Garden horticulturist Misty Minar distributes ladybugs to help control the aphid population inside Amazonia in Evansville last month. "We don't like to use pesticides, especially around the animals," said Minar, who explained that for every "bad" bug, there is a corresponding "good" bug to combat it.

"There are about 50 ladybugs in here," said Minar, a horticulturist and caretaker for Amazonia where 270 animals and about 5,000 plants coexist in humid comfort.

Actually, there are a lot more residents inside Amazonia if you include the good, the bad and the ugly of the bug world.

Mingling with these tiny insects — aphids, scales and mealybug destroyers to ladybugs, parasitic wasps and spider mites — is part of Minar's duties.

She doesn't wear a Pest Buster T-shirt, but her battle plan is set: Use good bugs against bad bugs to protect the exotic plants and trees that were custom grown for Amazonia when the exhibit's glass-and-waterfall world was taking shape two years ago.

"We don't use pesticides in Amazonia because of the animals, which include a pair of popular jaguar cubs, living in the building," she explained, standing near a pair of kapok and mahogany trees from Florida.

Her biological pest control methods — some call it integrated pest management — run the gamut from releasing ladybugs and parasitic wasps to strategically placing "beer traps" or creating bug spray out of coffee grounds and rubbing alcohol.

Here's how it works:

- Ladybugs: Every couple of months, 9,000 to 18,000 of them are delivered from GreenMethods, a 17-year-old New Hampshire company that stockpiles ladybugs from the foothills of the Sierra Nevada. Minar uses them in bunches as needed. Ladybugs, including the Asian lady beetles that invade Tri-State homes in the fall, control minuscule aphids that can damage plant leaves. Ladybugs also eat other soft-bodied pests.

- Parasitic wasps are so tiny, they are barely visible. In fact, 30,000 of them could fit in the ladybug container, said Minar.

The tiny wasps sting scales and deposit their eggs in them. When the eggs hatch, the larvae eat the scale, emerge as adult wasps and the process starts over.

Recently, to tackle the big Smoky Brown and Australian cockroaches that arrive via the plants, the zoo hung tiny tubes on various plants. Inside each tube were parasitic wasp-infected roach eggs. Once the wasps hatch, they eat the baby roaches in the egg case, then fly off to find other roach egg cases in Amazonia.

- Mealybug destroyers are beetles that lay their eggs in the cottony masses of mealybugs. The larvae eat the mealybug.

- A species of spider mite controls another more damaging species of spider mite without harming the plant.

Some of Minar's more unusual methods aren't fancy, but they work. For instance, she'll take soft drink cans, paint them black, add a little "cheap beer" to attract snails and position the "beer traps" out of public view.

"Snails love orchids," she explained while finding a can where several occupants had checked in. She'll also cover a small pickle jar with pantyhose (which helps the bug climb in), smear some Vaseline inside (just try to get out) and add a little bread and beer to lure a roach or snail.

"I spent a lot of time in college studying horticulture, but I never thought I'd be collecting roaches," she said with a chuckle.

To make coffee spray that helps control scales, she runs water through the coffee pot a second time (after her husband has enjoyed his first pot of coffee.) She points out that coffee grounds in soil also can deter pests and be a good fertilizer.

Another bug spray is made with one part rubbing alcohol and four parts water.

Minar said preventive measures include inspecting plants before they enter Amazonia, removing pest-breeding sites and hosing down plants. To get an exact ID on the pest and develop the right "good bug" control, samples are sent to Purdue University's diagnostic laboratory.

Minar said eventually the good bugs being released will establish colonies to help control the pest population on their own.